Calculates autoecological data (optima and tolerance ranges) of a biological species
given an environmental matrix. The package calculates by weighted averaging, using the number of occurrences to adjust the
tolerance assigned to each taxon to estimate optima and tolerance range in cases where taxa
have unequal occurrences. See the detailed methodology by Birks et al. (1990) <doi:10.1098/rstb.1990.0062>, and a
case example by Potapova and Charles (2003) <doi:10.1046/j.1365-2427.2003.01080.x>.